CT characteristics of dehiscent sigmoid plates presenting as pulsatile tinnitus: a study of 23 patients

Multiphysics coupling numerical simulation of flow-diverting stents in the treatment of patients with pulsatile tinnitus

Patients with pulsatile tinnitus (PT) have unstable treatment effects after resurfacing surgery. Flow-diverting stents (FDS) are proposed as a potential method for the treatment of PT, but the therapeutic effect is not clear. This study aimed to investigate the efficacy of FDS in the treatment of patients with PT induced by sigmoid sinus diverticulum (SSD) and sigmoid sinus wall dehiscence (SSWD). In addition, we aimed to explore the treatment mechanism of PT. Transient-state multiphysics coupling numerical simulation method based on computed tomography angiography of five patients was used to clarify the biomechanical and acoustic states before and after FDS placement. FDS was placed to prevent the blood flow from impacting the vessel wall in the SSD and SSWD areas. Low blood flow velocity (<0.0391 m/s), high relative residence time (>10 Pa^-1 ), and low wall shear stress of SSD might lead to thrombosis after FDS placement. The average pressure on the SSWD area of each patient decreased by 13.77%, 18.82%, 29.23%, 19.03%, and 11.20%. The average displacement of the vessel wall on the SSWD area showed acute pulsation and decreased by 15.29%, 14.64%, 30.22%, 41.03%, and 21.28%. The average sound pressure level at the tympanum decreased by 14.01%, 9.33%, 17.66%, 18.88%, and 25.18%, respectively. In brief, FDS was placed to avoid blood flow impacting vessels and reduce the vibration of vessels in the short term, thereby attenuating the degree of PT. The long-term prognosis was that the SSWD area was blocked after SSD thrombosis. Therefore, FDS might be an effective method for the treatment of PT induced by SSD and SSWD. This study would provide a theoretical basis for the treatment of PT and an exploration of FDS design in the treatment of PT.

State of the Art: Venous Causes of Pulsatile Tinnitus and Diagnostic Considerations Guiding Endovascular Therapy

Venous variants and pathologic abnormalities are the most common causes of pulsatile tinnitus. These conditions include causes of turbulence within normally located veins and sinuses, and abnormally enlarged or abnormally located veins in close transmissive proximity to the conductive auditory pathway. Such disorders include pathologic abnormalities of the lateral sinus (transverse sinus stenosis and sigmoid sinus wall anomalies), abnormalities and variants of the emissary veins, and anomalies of the jugular bulb and jugular vein. Despite being the most common causes for pulsatile tinnitus, venous variants and pathologic abnormalities are often overlooked in the workup of pulsatile tinnitus. Such oversights can result in delayed patient care and prolonged patient discomfort. Advances in both cerebrovascular imaging and endovascular techniques allow for improved diagnostic accuracy and an increasing range of endovascular therapeutic options to address pulsatile tinnitus. This review illustrates the venous causes of pulsatile tinnitus and demonstrates the associated endovascular treatment. © RSNA, 2021.

Hemodynamic Changes in the Sigmoid Sinus of Patients With Pulsatile Tinnitus Induced by Sigmoid Sinus Wall Anomalies

OBJECTIVE

This study is to investigate the hemodynamic changes of pulsatile tinnitus (PT) patients induced by sigmoid sinus wall anomalies (SSWA).

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral university hospital.

PATIENTS

Fifteen unilateral PT patients with SSWA identified on computed tomography images and surgery and 15 age-, sex-, and body mass index-matched healthy volunteers underwent velocity-encoded, cine magnetic resonance imaging.

INTERVENTION

Hemodynamic data in sigmoid sinus were obtained from velocity-encoded, cine magnetic resonance imaging, and compared between PT patients and controls.

MAIN OUTCOME MEASURES

Heart rate was recorded. Cross-sectional area (CSA), peak positive velocity (PPV), average positive flow volume per beat (APFV/beat), average flow volume per beat (AFV/beat), peak negative velocity (PNV), and average negative flow volume per beat (ANFV/beat) were measured. Average flow volume per minute (AFV/min), average positive flow volume per minute (APFV/min), average negative flow volume per minute (ANFV/min), average positive velocity (APV), average negative velocity (ANV), and regurgitation fraction (RF) were calculated.

RESULTS

APV at PT side of patients was 13.4 ± 3.3 cm/s, which was significantly slower than that at corresponding side of controls (15.8 ± 2.6 cm/s). PNV and RF at PT side of patients were 21.0 ± 15.4 cm/s and 2.4% respectively, which were significantly higher than those values at corresponding side of controls (both of them were 0). HR, CSA, PPV, APFV/beat, APFV/min, AFV/beat, AFV/min, ANV, ANFV/beat, and ANFV/min were 69.8 ± 9.4 beat/min, 48.4 ± 17 mm, 31.4 ± 5.9 cm/s, 5.4 ± 1.8 ml/beat, 373.9 ± 117.7 ml/min, 5.1 ± 2.0 ml/beat, 352.0 ± 134.6 ml/min, 2 (0-4.9) cm/s, 1 (0-2.7) ml/beat, and 4.1 (0-141.3) ml/min at PT side of patients, and 67.4 ± 7.8 beat/min, 38.2 ± 18 mm, 29.9 ± 3.9 cm/s, 5.3 ± 2.0 ml/beat, 350.3 ± 125.3 ml/min, 5.1 ± 1.9 ml/beat, 340.5 ± 117.9 ml/min, 0 (0-2.1) cm/s, 0 (0-0.8) ml/beat, and 0 (0-55.4) ml/min at corresponding side of controls. These hemodynamics were not significantly different between groups.

CONCLUSION

APV, PNV, and RF changes take place in SSWA patients, which may be associated with the occurrence of PT and have the potential value to improve accurate etiological diagnosis and predict treatment success.

Hemodynamic study on the different therapeutic effects of SSWD resurfacing surgery on patients with pulsatile tinnitus

Sigmoid sinus wall anomalies (SSWA) are a common pathophysiology of pulsatile tinnitus (PT) and usually treated by sigmoid sinus wall dehiscence (SSWD) resurfacing surgery. However, symptoms of tinnitus remain unrelieved after surgery in some patients with PT, and even new tinnitus appears. The cause of the difference in therapeutic effects is unclear. In this study, eight patient-specific SSWA geometric models were reconstructed on the basis of computed tomography angiography, including four cases of postoperative rehabilitation (group 1, 1-4 cases) and four cases of non-rehabilitation (group 2, 5-8 cases). Transient-state computational fluid dynamics (CFD) was performed to clarify the SS blood flow pattern and hemodynamic states. The wall pressure distribution on SSWA area, pressure difference, and flow pattern in SS were calculated to evaluate the hemodynamic changes of rehabilitation and non-rehabilitation patients before and after surgery. The difference of hemodynamics between these patients was statistically analyzed. The accuracy of CFD simulation was evaluated by cross validating the numerical and particle image velocimetry experimental results. Results showed that the SSWA area in patients with PT was loaded with high pressure. No difference was found in the hemodynamic characteristics between the two groups pre- and postoperation. When the average pressure (P_avg) and time-average P_avg (TAP_avg) on the SSWA area were studied, the TAP_avg difference pre- and postoperation between the two groups was found significant (p = 0.0021). The TAP_avg difference had a negative change in postoperative rehabilitation patients (case 1, -44.49 Pa vs. case 2, -15.85 Pa vs. case 3, -25.88 Pa vs. case 4, -16.58 Pa). The postoperative TAP_avg of non-rehabilitation patients was higher than the preoperative one (case 5, 24.70 Pa vs. case 6, 28.56 Pa vs. case 7, 5.81 Pa vs. case 8, 13.04 Pa). The velocity streamlines in the SS with rehabilitation became smoother and more regular than that without rehabilitation. By contrast, the velocity streamlines in SS without rehabilitation showed increased twisting and curling. No difference was found in time-average volume-averaged vorticity (TAV_avgV) between the two groups. Therefore, the high pressure of the vessel wall on SSWA area was one of the causes of PT. The variation of SSWA wall pressure difference before and after PT was the cause of the difference in therapeutic effects after SSWD resurfacing surgery. In patients with SSWA, disordered blood flow in SS was another cause of PT. SSWD repair may relieve tinnitus to some extent, but blood flow disorders may still arise.

A study on relationship between pulsatile tinnitus and temporal bone pneumatization grade

Pulsatile tinnitus (PT) is a common symptom in otology. In some cases, the venous flow in the sigmoid sinus (SS) is the source of PT. It is suggested that the venous sound is propagated into the tympanic cavity through the air pathway of temporal bone air cells (TBAC). The hyperpneumatization of TBAC was hypothesized as a direct pathology of PT through amplifying the venous sound, but there is no quantitative analysis. This study aims to quantify the relationship between the venous sound amplification and the pneumatization grade of TBAC. The acoustic numerical simulation and statistical analysis were performed based on the radiology data of 21 pulsatile tinnitus patients. The TBAC of these patients were classified into hypopneumatization, normal pneumatization and hyperpneumatization grades according to three standards. The in vitro acoustic experiment was done as the validation of simulation. It is indicated that the SS standard is effective for the clinical evaluation of venous sound amplification. The TBAC amplifies the venous sound due to the acoustic resonance at the first mode frequency, regardless of the pneumatization grades. The normal pneumatic TBAC exhibits the highest sound amplification effect on the venous sound amongst the three grades, contributing mostly to PT, but would not induce PT without any other causes.

Systematic Review of Temporal Bone-Resurfacing Techniques for Pulsatile Tinnitus Associated with Vascular Wall Anomalies

OBJECTIVE

To systematically review literature evidence on temporal bone-resurfacing techniques for pulsatile tinnitus (PT) associated with vascular wall anomalies.

DATA SOURCES

We searched PubMed, Embase, and the Cochrane Database. The period covered was from 1962 to 2018.

REVIEW METHODS

We included studies in all languages that reported resurfacing outcomes for patients with PT and radiographic evidence or direct visualization of sigmoid sinus wall anomaly, jugular bulb wall anomaly, or dehiscent or aberrant internal carotid artery.

RESULTS

Of 954 citations retrieved in database searches and 5 citations retrieved from reference lists, 20 studies with a total of 141 resurfacing cases involving 138 patients were included. Resurfacing outcomes for arterial sources of PT showed 3 of 5 cases (60%) with complete resolution and 2 (40%) with partial resolution. Jugular bulb sources of PT showed 11 of 14 cases (79%) with complete resolution and 1 (7%) with partial resolution. Sigmoid sinus sources of PT showed 91 of 121 cases (75%) with complete resolution and 12 (10%) with partial resolution. Symptoms occurred more in females and on the right side. Most cases (94%) used hard-density materials for resurfacing. Material density did not appear to be associated with resurfacing outcomes. Use of autologous materials was associated with improved outcomes for arterial sources resurfacing. Major complications involving sigmoid sinus thrombosis or compression were reported in 4% of cases without long-term morbidity or mortality.

CONCLUSIONS

Resurfacing surgery is likely effective and well tolerated for select patients with PT associated with various vascular wall anomalies.

An in vitro experimental study on the relationship between pulsatile tinnitus and the dehiscence/thinness of sigmoid sinus cortical plate

Pulsatile tinnitus (PT), characterized as pulse-synchronous, is generally objective. Sigmoid sinus (SS) venous sound is widely suggested to be a possible sound source of PT. The dehiscence and thinness of SS cortical plate (CP) was commonly reported as PT pathology in previous studies, but lack quantitative or biomechanical analysis. In this study, it was aimed to quantify the relationship between venous sound and CP dehiscence/thinness using in vitro experiment. The in vitro models of SS and CP were established based on 3D-printing, with the developed pulsatile venous flow in the SS model. The generated sound signal and the vibration response at the dehiscent/thinned area were analyzed. The sound signal generated in the normal-sized dehiscence model was pulse-synchronous within 100--400 Hz, which had similar acoustic characteristics as the clinical PT sounds. It was concluded that the pulsatile venous sound is produced at TS-SS junction in case of CP dehiscence. The CP, even a thinned one can effectively diminish the venous sound and sound-generating pulsatile vibration at TS-SS junction. The CP dehiscence would induce pulse-synchronous and high pressure venous sound, as well as pulse-synchronous vibration above 20 Hz, regardless of the dehiscence size. On the contrary, the CP thinness would not induce obvious venous sound or pulsatile vibration above 20 Hz.

Evaluation and treatment of pulsatile tinnitus associated with sigmoid sinus wall anomalies

OBJECTIVE

Describe clinical and radiographic features of sigmoid sinus wall anomalies (SSWA) associated with pulsatile tinnitus (PT) and determine factors predictive of response to surgery.

METHODS

Preoperative diagnostic imaging and treatment response were reviewed after surgical repair of 40 ears among 38 consecutive patients presenting with PT associated with SSWA who underwent transtemporal sinus wall reconstruction.

RESULTS

Twenty-three ears had isolated sigmoid sinus dehiscence, and 17 had diverticulum. The rates of transverse sinus stenosis (TSS) and empty sella, 66% and 32% respectively, were significantly higher than in historical controls (P = 0.02 and 0.001). Thirty-six out of 40 subjects (90%) had complete resolution of their PT following surgery, including all those with a diverticulum. For subjects with dehiscence alone without diverticulum, a favorable response to surgery was strongly associated with the presence of TSS (P = 0.01) and empty sella (P = 0.02).

CONCLUSION

Sigmoid sinus diverticulum and dehiscence are a clinically important cause of PT. Women of childbearing age with an elevated body mass index (BMI) are commonly affected, and there is a high rate of associated TSS and empty sella. Transtemporal sinus wall reconstruction has a high rate of success in appropriately selected patients. Patients with isolated sinus wall dehiscence without diverticulum, TSS, or empty sella are less likely to respond to transtemporal sinus wall reconstruction. These data imply a multifactorial cause of PT in at least some patients with SSWA.

LEVEL OF EVIDENCE

4 Laryngoscope, 128:S1-S13, 2018.

Lateralization effects on functional connectivity of the auditory network in patients with unilateral pulsatile tinnitus as detected by functional MRI

Unilateral pulsatile tinnitus (PT) was proved to be a kind of disease with brain functional abnormalities within and beyond the auditory network (AN). However, changes in patterns of the lateralization effects of PT are yet to be established. Relationship between the AN and other brain networks in PT patients is also a scientific question need to be answered. In this study, we recruited 23 left-sided, 23 right-sided PT (LSPT, RSPT) patients and 23 normal controls (NC). We combined applied independent component analysis and seed-based functional connectivity (FC) analysis to investigate alteration feature of the FC of the AN by using resting-state functional magnetic resonance imaging (rs-fMRI). Compared with NC, LSPT patients demonstrated disconnected FC within the AN on both sides. Disrupted network integrity between AN and several brain functional networks, including executive control network, self-perceptual network and the limbic network, was also demonstrated in LSPT patient group bilaterally. In contrast, compared with NC, RSPT demonstrated decreased FC within the AN on the left side, but significant increased FC within the AN on the right side (symptomatic side). Enhanced FC between AN and executive control network, self-perceptual network and limbic network was also found mainly on the right side in patients with RSPT. Positive FC between the auditory network and the limbic network may be a reason to explain why RSPT patients are willing to be in the clinic. Briefly, LSPT exhibit disrupted network integrity in brain functional networks. But RSPT is featured by enhanced FC within AN and between networks, especially on the right (symptomatic) side. Corroboration of featured FC helps to reveal the pathophysiological changing process of the brain in patients with PT, providing imaging-based biomarker to distinguish PT from other kind of tinnitus.

Radiologic features of vascular pulsatile tinnitus - suggestion of optimal diagnostic image workup modalities

OBJECTIVES

The aim of this study was to determine the optimal diagnostic workup modalities for vascular pulsatile tinnitus through analysis of clinical and radiologic findings.

MATERIALS AND METHODS

A total of 49 patients diagnosed with vascular pulsatile tinnitus along with their medical records and radiologic findings were thoroughly reviewed.

RESULTS

Of these patients, 84% had venous lesions. The jugular bulb variants (67%) were the most common venous lesions followed by sigmoid sinus variants (12%). About 88% (43/49) of these lesions were detected with computed tomography of the temporal bone (TBCT) alone and the lesions were either venous or intratemporal artery in origin. Simple manual neck compression test was 93% sensitive in predicting venous lesions. A high suspicion for venous lesion coupled with manual neck compression test and selection of the optimal imaging technique are useful for the proper evaluation of vascular pulsatile tinnitus at the initial visit.

CONCLUSION

Our stepwise strategy may increase the cost-effectiveness of the chosen imaging workup by reducing redundancy of multiple and simultaneous radiologic tests in patients with vascular pulsatile tinnitus.

Sigmoid Sinus Diverticulum, Dehiscence, and Venous Sinus Stenosis: Potential Causes of Pulsatile Tinnitus in Patients with Idiopathic Intracranial Hypertension?

BACKGROUND AND PURPOSE

Pulsatile tinnitus is experienced by most patients with idiopathic intracranial hypertension. The pathophysiology remains uncertain; however, transverse sinus stenosis and sigmoid sinus diverticulum/dehiscence have been proposed as potential etiologies. We aimed to determine whether the prevalence of transverse sinus stenosis and sigmoid sinus diverticulum/dehiscence was increased in patients with idiopathic intracranial hypertension and pulsatile tinnitus relative to those without pulsatile tinnitus and a control group.

MATERIALS AND METHODS

CT vascular studies of patients with idiopathic intracranial hypertension with pulsatile tinnitus (n = 42), without pulsatile tinnitus (n = 37), and controls (n = 75) were independently reviewed for the presence of severe transverse sinus stenosis and sigmoid sinus diverticulum/dehiscence according to published criteria. The prevalence of transverse sinus stenosis and sigmoid sinus diverticulum/dehiscence in patients with idiopathic intracranial hypertension with pulsatile tinnitus was compared with that in the nonpulsatile tinnitus idiopathic intracranial hypertension group and the control group. Further comparisons included differing degrees of transverse sinus stenosis (50% and 75%), laterality of transverse sinus stenosis/sigmoid sinus diverticulum/dehiscence, and ipsilateral transverse sinus stenosis combined with sigmoid sinus diverticulum/dehiscence.

RESULTS

Severe bilateral transverse sinus stenoses were more frequent in patients with idiopathic intracranial hypertension than in controls (P < .001), but there was no significant association between transverse sinus stenosis and pulsatile tinnitus within the idiopathic intracranial hypertension group. Sigmoid sinus dehiscence (right- or left-sided) was also more common in patients with idiopathic intracranial hypertension compared with controls (P = .01), but there was no significant association with pulsatile tinnitus within the idiopathic intracranial hypertension group.

CONCLUSIONS

While our data corroborate previous studies demonstrating increased prevalence of sigmoid sinus diverticulum/dehiscence and transverse sinus stenosis in idiopathic intracranial hypertension, we did not establish an increased prevalence in patients with idiopathic intracranial hypertension with pulsatile tinnitus compared with those without. It is therefore unlikely that these entities represent a direct structural correlate of pulsatile tinnitus in patients with idiopathic intracranial hypertension.

Aberrant sylvian vein: A newly described cause of pulsatile tinnitus

We herein report a newly described cause of venous pulsatile tinnitus: protrusion of an aberrant sylvian vein into the tympanum. A 60-year-old woman presented with a 4-month history of objective persistent pulsatile tinnitus in the right ear with no other complaints. The pulsatile tinnitus diminished with rotation of the head to the right side or by compression of the right cervical vascular structures. The frequency and intensity of the tinnitus were 125 Hz and 20 dB HL, respectively. Audiometry and otoscopic examination findings were normal. Radiologic examination showed that the right sylvian vein protruded into the tympanum through the dehiscent anterior cortical plate of the tympanum.